Fluid Servo Valve and Fluid Servo Apparatus

• US 20160228889A1
• Filed: 02/09/2016
• Published: 08/11/2016
• Est. Priority Date: 02/10/2015
• Status: Active Grant

• Current Assignee: Tokkyokiki Corporation
• Original Assignee: Tokkyokiki Corporation
• Inventors: Okada, Takumi, Nakashima, Masataka, Maruyama, Teruo, Okamoto, Kozo, Yamaguchi, Satoki
• Granted Patent: US 10,465,816 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F15B 13/02 Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
• CPC Class Codes: F15B 5/003 characterised by variation of the pressure in a nozzle or the like, e.g. nozzle-flapper system
• CPC Class Codes: F16K 31/0606 fluid passing through the solenoid coil
• CPC Class Codes: F16K 31/0641 the valve member being a diaphragm
• CPC Class Codes: F16K 31/0651 the fluid passing through the solenoid coil
• CPC Class Codes: F16K 31/0672 the valve member being a diaphragm
• CPC Class Codes: F16K 31/0675 Electromagnet aspects, e.g. electric supply therefor
• CPC Class Codes: F16K 31/128 servo actuated
• CPC Class Codes: H01F 7/13 characterised by pulling-force characteristics
• CPC Class Codes: H01F 7/1805 Circuit arrangements for holding the operation of electromagnets or for holding the armature in attracted position with reduced energising current for holding relay armature in attracted position with reduced energising current H01H47/04; quick energising of electro-dynamic machines H02P9/08; for quickly de-energising of dynamo-electric generators H02P9/123
• CPC Class Codes: Y10T 137/86598 Opposed orifices; interposed modulator

Abstract

The present invention controls the pressure and flow rate of fluid, in order to obtain uniform performance, configure a closed loop magnetic circuit so as to include an electromagnet, a flapper, and a yoke material, and elastically deform the flapper itself by Maxwell attractive force generated between a magnetic pole of the electromagnet and the flapper to make the separation distance between the nozzle and the flapper variable. As opposed to a rigid flapper structure that swingably moves around a supporting point, like a conventional servo valve, the electromagnet, the magnetic pole, the nozzle, the flapper, and the like are arranged such that a change in magnetic gap directly leads to a change in air gap.

Claims

1. A fluid servo valve comprising:

a nozzle of which a flow path is connected to a fluid supply source;

a flapper that is provided so as to face toward a tip part of the nozzle;

a flapper supporting member that fixes a part of the flapper; and

an electromagnet that is provided so as to generate an attractive force on the flapper,

the fluid servo valve being configured to deform the flapper by the attractive force of the electromagnet to change a separation distance between the tip part of the nozzle and the flapper.

2. The fluid servo valve according to claim 1, configured such that:

the fluid supply source is adapted to supply air;

the electromagnet, the flapper, and the flapper supporting member constitute an actuator part; and

fluid passing through the nozzle passes through a space formed by respective wall surfaces of the respective members constituting the actuator part.

6. The fluid servo valve according to claim 1, wherein

the flapper is formed of a substantially flat-plate-shaped member, and elasticity of the flapper itself is used to give the flapper a restoring force proportional to a size of a gap between the nozzle and the flapper.

8. The fluid servo valve according to claim 6, wherein:

the electromagnet comprises

a first magnetic pole that is formed on an inner end surface facing toward the flapper, and

a second magnetic pole that is formed on an outer end surface facing toward the flapper;

the flapper comprises

a magnetic path part where a part between the first magnetic pole and the second magnetic pole is formed in the closed loop magnetic circuit formed by the electromagnet, and

an elastically supporting part that is supported by the flapper supporting member and elastically supports the magnetic path part; and

the magnetic path part and the elastically supporting part are different in flexural stiffness.

9. The fluid servo valve according to claim 1, wherein

nozzles are provided in two positions, one of the nozzles is provided on a fluid supply side and configured as a forward nozzle, the other nozzle is provided on a fluid exhaust side and configured as a reverse nozzle, and the forward nozzle, the reverse nozzle, and the flapper constitute a bidirectional nozzle flapper valve,

the fluid servo valve being configured such that working fluid supplied from the fluid supply source passes through the forward valve from a supply source side, flows into a control chamber as a space containing the flapper, passes through the reverse nozzle from the control chamber, and flows out to the fluid exhaust side, wherein

the reverse nozzle is arranged substantially coaxially with the forward nozzle and on a side opposite to the flapper.

10. The fluid servo valve according to claim 1, wherein

an intake port is connected to the fluid supply source, a flowmeter is attached to a flow path connecting from a control chamber to atmospheric air, and when a linearization effect index η

=α

/β

is defined, given that a flow rate measured by the flowmeter at a maximum value I_max (A) of current applied to the electromagnet is denoted by Q_max (L/min), a gradient Q_max/I_max is defined as a reference flow rate gain α

, and a maximum value of the gradient is defined as a maximum flow rate gain β

in a profile of a flow rate characteristic with respect to the input current, η

>

0.2.

11. The fluid servo valve according to claim 1, wherein:

the electromagnet is configured to include a supporting shaft made of a magnetic material, a coil wound with the supporting shaft as a shaft center, and a tubular part that is arranged so as to contain the coil and made of a magnetic material; and

the supporting shaft, the flapper, and the tubular part constitute a closed loop magnetic circuit.

12. The fluid servo valve according to claim 11, wherein

a circulation path that penetrates through the supporting shaft and is connected to a fluid supply side or a fluid exhaust side is formed, and the nozzle is provided at a flapper side opening end of the circulation path.

13. The fluid servo valve according to claim 11, wherein:

the flapper comprises an elastic deformation part that is formed in a plate shape and configured to be deformable toward the nozzle;

the electromagnet comprises a magnetic pole that is formed on an end surface facing toward the flapper; and

the flapper is formed in a plate shape and faces toward the magnetic pole in a central part, and the elastic deformation part is defined by a through-hole that is formed between the central part of the flapper and the flapper supporting member and penetrates in a thickness direction in the flapper.

14. The fluid servo valve according to claim 1, wherein:

an annular flow path forming structure forming a flow path having a substantially annular cross section is formed between the nozzle and the flapper; and

the annular flow path forming structure includes

a tubular inner circumferential surface that forms an outer boundary of the flow path having the substantially annular cross section, and

an insertion body that is inserted separated radially from the inner circumferential surface.

15. The fluid servo valve according to claim 14, wherein:

between a forward nozzle and the flapper and between a reverse nozzle and the flapper, annular flow path forming structures are respectively formed; and

the fluid servo valve being configured such that fluid passes through the forward nozzle from a supply source side, flows into a control chamber as a space containing the flapper, passes through the reverse nozzle from the control chamber, and flows out to a fluid exhaust side.

16. The fluid servo valve according to claim 14, wherein:

the tubular inner circumferential surface is an inner circumferential surface of the tip part of the nozzle; and

the insertion body is a substantially conical-shaped convex part formed on a face plate part of the flapper.

17. A fluid servo apparatus comprising:

the fluid servo valve according to claim 1;

a sensor adapted to detect a vibration state of a control target; and

control means adapted to give gas pressure for controlling the vibration state of the control object to a pneumatic actuator by adjusting the fluid servo valve on a basis of information from the sensor.

18. The fluid servo apparatus according to claim 17, comprising:

a gas spring that fixes a primary natural vibration frequency of the flapper to 200 Hz or more and supports a vibration isolation target with respect to a base;

the fluid servo valve that supplies gas from a supply side to the gas spring, and exhausts the gas to an exhaust side;

an acceleration sensor that detects a vibration state of the vibration isolation target; and

active control means adapted to give gas pressure for reducing vibration of the vibration isolation target to the gas spring by adjusting the fluid servo valve on a basis of information from the acceleration sensor.

3. A fluid servo valve comprising:

a nozzle of which a flow path is connected to a fluid supply source;

a flapper that is provided so as to face toward a tip part of the nozzle;

a flapper supporting member that supports the flapper;

an electromagnet that is provided so as to generate an attractive force on a face plate part of the flapper; and

a closed loop magnetic circuit that is configured to include at least the electromagnet and the flapper,

the fluid servo valve being configured to displace the flapper by the attractive force of the electromagnet to change a separation distance between the tip part of the nozzle and the flapper, wherein

a magnetic characteristic of a magnetic material component constituting the closed loop magnetic circuit has;

a linear region where a magnetic flux density characteristic with respect to magnetizing force exhibits a substantially proportional relationship; and

a magnetic saturation region where a tilt angle of the magnetic flux density characteristic with respect to the magnetizing force changes small as compared with the tilt angle in the linear region, and

when increasing current applied to the electromagnet, the magnetic flux density that flows in the magnetic material component enters the magnetic saturation region at the smaller displacement of the flapper than the max value of the displacement of the flapper.

4. The fluid servo valve according to claim 3, wherein

given that at a maximum value I_max of the current value applied to the electromagnet, total linear magnetic resistance of the closed loop magnetic circuit is denoted by R_s, the number of turns of a coil of the electromagnet is denoted by N, magnetic flux is denoted by Φ

_max=N×

I_max/R_s, a magnetic path area of the magnetic material component is denoted by S_c, and magnetic flux is denoted by B_max=Φ

_max/S_c in the magnetic flux density characteristic of the magnetic material component with respect to the magnetizing force, a magnetic flux density boundary value at a boundary between the linear region and the magnetic saturation region is <

B_max.

5. The fluid valve according to claim 4, wherein

at near the maximum value of the current applied to the electromagnet, a flow rate characteristic with respect to the current exhibits an upward convex curve.

7. The fluid servo valve according to claim 4, wherein

the flapper is the magnetic material component.

19. A fluid servo valve comprising:

an electromagnet;

a flapper, and a flapper supporting member adapted to support the flapper, wherein the electromagnet, the flapper, and a yoke material constitute a closed loop magnetic circuit;

an output shaft that can be moved by Maxwell attractive stress generated between the electromagnet and the flapper and is fixed to the flapper, wherein a part configured to include the electromagnet, the flapper, the supporting member, the yoke material, and the output shaft is used as a microactuator part; and

a housing, and fluid intake and ejection ports formed in the housing, and a flow rate regulation valve adapted to regulate an opening level of a flow path connecting between the intake port and the ejection port, wherein the flow rate regulation valve is driven by the output shaft of the microactuator part, wherein

a magnetic characteristic of a magnetic material component constituting the closed loop magnetic circuit is defined so as to include;

a linear region where a magnetic flux density characteristic with respect to magnetizing force exhibits a substantially proportional relationship; and

a saturation region where a tilt angle of the magnetic flux density characteristic with respect to the magnetizing force changes small as compared with the tilt angle in the linear region, and when the magnetic flux density that flows in the magnetic material component enters the magnetic saturation region at the smaller displacement of the flapper than the max value of the displacement of the flapper.

20. The fluid servo valve according to claim 19, wherein

the output shaft is provided penetrating through a central part of the electromagnet.